One of the goals of the Affordable Care Act (ACA) was to increase the fraction of Americans covered by health insurance. That’s why pundits have seized upon a recent Gallup poll, showing that the share of uninsured Americans declined 1.5 percentage points in the last three months. To supporters of Obamacare, the survey is evidence of the new law’s success.

But I’m not so sure.

While the survey shows that the fraction of uninsured Americans declined from 17.1 percent to 15.6 percent over the last quarter, it also shows that the share rose from 16.4 percent in the first three months of 2010 to 18 percent in the third quarter of 2013. That means the fraction of uninsured Americans only declined 0.8 percentage points between the time the law was passed and now. Because the survey’s margin of error is plus or minus one percentage point, the 2010 and 2014 numbers are statistically indistinguishable.

Moreover, the decline is far from what the law’s proponents claimed it would be. The White House has claimed the ACA will reduce the number of uninsured Americans by 32 million by the time it is fully implemented in 2018. Given the Census Bureau’s population projections, that works out to only 5.5 percent of Americans being uninsured. I don’t think a 0.8 percentage point decline in the share of uninsured at the half way point to implementation means the law is “on track” to reduce the fraction by 10.9 percentage points by 2018.

Furthermore, the ACA may not even be responsible for the recent decline in the fraction of uninsured Americans. The shift could easily be the result of a stronger economy. A more robust economy would motivate companies to hire more workers, some of whom will receive employer-sponsored health insurance. It would also lead businesses to offer health care benefits to a larger fraction of their workers. Both of those things could have happened in the absence of passage of the ACA.

Many of the newly insured are probably getting coverage because they found jobs at places that provide insurance. A recent RAND Corporation study shows that 57 percent of the people who went from being uninsured in 2013 to being insured in 2014 obtained employer coverage. While the authors of the study suggest that the individual and employer mandates might somehow be responsible, those explanations are hard to believe. The fraction of employers offering employee health care coverage has declined steadily since 2010, suggesting that the employer mandate is not encouraging more companies to cover employees. In addition, the 2014 ADP Health Benefits Report reveals that the fraction of Americans employed full time who participate in their employers’ health care plans declined from 68 percent to 67 percent between 2010 and 2014. If the individual mandate were spurring more employees to take up their employers’ offers of insurance, then the fraction of employees participating in their employers’ coverage should be rising.

The evidence is also scant that the new federal and state health insurance exchanges are reducing the fraction of uninsured Americans. The RAND study shows that only about 11 percent of people who transitioned from uninsured obtained their insurance through the state and federal marketplaces. Moreover, studies by McKinsey and RAND report that only 27 percent and 33 percent of those signing up on the new exchanges, respectively, were previously uninsured.

By the time it is fully implemented in 2018, the ACA might help to reduce the fraction of uninsured Americans. But, for now, its supporters should not interpret small declines in the share of uninsured share as evidence that the law is moving this nation toward nearly universal health insurance coverage.